In such a fanfiction, the plot could involve Naruto growing up with Itachi as his father figure. He might inherit some of Itachi's unique abilities like the Sharingan in a unique way. Maybe he would face different challenges in the ninja world, as people would react differently to him being the son of Itachi. Also, his relationships with other characters like Sasuke would be very different, perhaps a more brotherly bond from the start.
In this fanfiction, Naruto's character would be a blend of his own exuberant self and Itachi's more solemn traits. He would be more perceptive, quickly understanding the motives of his enemies. His growth as a ninja would be faster in some aspects, like his ability to analyze battle situations due to Itachi's influence. He would also have a different relationship with the Uchiha clan. Since he's Itachi's son, they might see him as a symbol of hope or a link to Itachi's true intentions. This would all contribute to a more complex and multi - faceted Naruto character.
Wonder Woman is another character that might be paired with Itachi. Her Amazonian warrior heritage and Itachi's shinobi skills can be compared and contrasted. Their different views on justice, with Wonder Woman coming from a more idealistic place and Itachi having a more pragmatic approach, can lead to some great character - driven storylines in fanfiction.
They could develop a mentor - mentee relationship. Itachi uses his knowledge of the Sharingan to teach Naruto new combat techniques. As they train together, they bond over their shared experiences of loss and their desire to protect the people they care about. Naruto might also help Itachi come to terms with his past actions and find some peace within himself.
Itachi's personality could become more outwardly friendly. In the ninja world, he had to keep many secrets and be aloof. But in the wizarding world as Harry Potter, he might find it easier to let people in. He may also be more assertive in a different way. Instead of silently following orders like in his past life, he could take the lead in situations, using his own judgment based on his past experiences and newfound magical knowledge.
Definitely include Obito. His complex relationship with the Uchiha clan and his own history with the Anbu - like Akatsuki could create some interesting plot twists. Additionally, Kurenai could be added. She could be involved in a mission where she has to work with Itachi and Naruto. Her genjutsu skills might come in handy during a crucial part of the story. And don't forget about Rock Lee. His determination and unique fighting style could add some action - packed scenes to the fanfiction, especially if he gets involved in a mission with Itachi and Naruto.
A possible relationship could be one of mutual respect. Sarada would respect Itachi for his skills and his past sacrifices. Itachi, on the other hand, might see Sarada as a symbol of hope for the future of the Uchiha clan. They could share stories about the Uchiha, with Itachi passing on the history and traditions that Sarada might not be fully aware of. This could strengthen their bond and lead to a deeper understanding between them. In the fanfiction, they might also team up to face a common enemy, relying on each other's strengths and abilities, which would further solidify their relationship.